Electric spark-plug.



NO.`8.73,968. PATBNTED DEG. 17,V 1907.

' P. B. THATGHER.

, ELECTRIC SPARK PLUG. APPLIOATION FILED JAN. 3 1. 1901.

Fig. '1

residing give a jump spark to ignite the Sbcing exposed to the air,

FREDERlCh'. B. THTGHER, OF PROVDENC, RHODE ISLAND ELECTRIC SPARK-PLUG.

Specification of Letters Patent.

Patented ZDec.' 1 7, 1907.

Application filed January 31| 1907. Serial No. 355.035.

To all lwho/n it 'may Conce/"a: Be it known that l, 'l`i-i.\'rcrinn, a citizen of the. United States, at Providence',4 in the county of Providence and State ol Rhode island, have invented a neuv and useful improvement in Electric Sparlo'llugs, of which the following is a specification.

rllhis'invention has rcllerenceto an iin-- provcmen'l in electric ignition dcijices for igniting the gas in hydrocarbon or internal combustimi engines and more particularly to an improvement in spark plugs adapted to gas in the en- Fnnnnnicii B.

gine.

In the 'usual construction of spark plugs the porcelain insulating core is formed integral. Then in use the inner end of the por celain core is in the explosion chamber or' the engine wl'ierc it is subjected to the intense heat of the explosions while the outer end, is comparatively cold. y this construction the sudden expansion of the inner end of the core caused by thc intense heat in the engine is liable to and docs at times break the porcelain core, thereby ruining the utility of the plug and disabling the engine.

The object ot' my `inventioi'i is to improve the construction of a spark plug, whereby the inner cnd ol the porcelain core is constructed separate from the outer end and insulated from the same io a large extent by a washer of asbestos or other material. An. additional packing is lormcd by the washer between the core and the shell of the plug to prevent leakF age from the engine and` the sparking point and terminal are constructed to give a more perfect ignition than has heretofore been attained.

` My invention consists in the peculiar and novel construction of aspark plug, as will be more fully set forth harem-after and claimed.

'Figure 1 is a side view of my improved spark plug. YF 2 is a longitudinal sectional 'View through the spark plug, showing the construction of the plug, and Fig. 3 is an end view looking at the ignition end of the plug` ln the drawings, a indicates the outer shell, t the packing sleeve7 c the inner member, and

4members c and d of the core.

l the outer'member of the porcelain core, e the sparkii'ig point rod, and f theA fastening nut ol" vmy improved spark p ug.

rl`he shell a has a body portion 4l in the form oi" a nut with a cylindrieal'screW-tlneaded open inner end 5 having oppositely-disposedv openings' 5a 5a formed in the side ol. the end 5 and extending inward from the end, around wire sparking terminal 6 secured at cach end in the wall of the end 5 adjacent the open end and extending centrally across the end, as shown .in Figs. 2 and 3, an

iiiter-nally-screw-threaded chamber 7 in the body -1 and a central .bore 8 extending from the chamber 7 into the cylindrical end 5 and forming an internal annular shoulder 9 at the inner end of the chamber 7.

The packing sleeve vbis adapted to screw into the chamber 7 and has a central bore 10, as shown in 'l ig. 2.

The inner member c of the porcelain core has an annular lip 11 on its inner end in the chamber 7, and a central longitudinal hole 12, and extends into the cylindrical end 5. The outer member d of the porcelain core has an annular lip 1R on its inner end in the chamber 7 and a central longitudinal hole 14 and extends outward through the bore 10 in the aching sleeve l). Packingrings 15 15 of as liestos or other material are placed intermediate the annular shoulder 9 and the annular lip 1l andthe annular lip 13 and the inner end of the packing sleeve l), and a combined insulating and packing washer 1li of asbestos or other non-heat conducting matti =al is placed intermediate the flat inner ends of the members c and d ol'l the core.

The sparking point rod c hasa sparking point 17 adjacent the sparking terminal 6, a nut-shaped collar 18 adjacent the point 17, and a screw-threaded end 19. This rod e extends through the holes 12 and 14 in the A packing is placed on the rod inring 2() ofkasbestos 1S and the end of the termedi ate the collar member c of the core.

The 'fastening nut f onto the end, 19 of the rod e the end of the porcelain core. may have an annular groove Z1 to receive a special Wirey connection or may be constructed to receive any of the well known forms of electric wire connections. By tightening the nutf'on the end of the rod e the members c and d of the core are drawn together, the washer 16 is compressed between the ends of themembers and forced outward against the Wall of the chamber 7 thereby forming an additional packing to prevent leakage from the engine through the chamber in addition to its function of thermally insulating the members c and d.

is adapted to screw and abut agamst This nut f c.

The packing ring 2G is compressed between i the collar 1S andthe end of themember e of the core, therebyT preventing leakage from the engine through the holes 12 and i4 in the members c and ci oi the' core, and by tighten ing the sleeve b the core is firmly secured in the shell a. in a position to bring the sparking point 17 the required distance from the spark-ing terminal 6, as shown in Fig. 2.

In the use of my improved spark plug, i find that there is no liability of the porcelain cores breaking through heat irom the engine, no loss of power in the engine due to escape ol gas through the plug, and by the transverse position of the wire sparking terminal G relative to the sparking point 17 the flame generated by the spar Az strikes the wire terminal and spreads fan-shape into the explosion chamber, thereby giving a more periect combustion and increasing the power of the engine. The outer end of the porcelain core being separate from the inner end may be given a slight lateral movement by aceident or other causes, without breaking the core or changing the sparking point i?, relative to the sparking terminal n.

itl'aving thus described my invention I claim as new and desire to secure by Letters Patent,`

l. In a spark plug, an outer shell having one end formed with screw threads on its interior and its opposite end formed vwith screw threads on its exterior, a shoulder' formed on the interior of sai d shell intermediate its length, an outer core member extending in one end of said shell, and having an inner annular lip, a packing sleeve around said outer member engaging said interior i wire terminal l l r l l extending through said core members, a'

sparking point on said said enlarged interior of the shell, a col ar on said rod to the rear of said point abutting said inner core member, said end of the shell surrounding` the innerv oore member being formed which expose said rod projectin into sparking point, and a secured to said last named end of the shell'at right angles to said openings thereof.

in a spark plug an outer shell, an inner and an out-er eore member in said shell, a sparking point rod extending through said members, a sparking point on said rod, a collar on the rod to the rear of said point abutting said inner core member, said shell being formed with an extension which incioses said inner core memberand projects therebeyond, said extension being formed with a pair ol a ilelgith to expose said spar ing point, and a Wire terminal secured tosaid extension bej-*ond'said sparking point.

`[n testimony whereof `I have signed my naine to this spoeification in the presence of two subscribing witnesses.

FREDERICK THATCHER. Witnesses:

Ana E. J. A.

HAGERTY,

with two oppositelj,r disposed openings of oppositely disposed openings 

